This film is from the same team behind the legendary Godzilla (1954), here abandoning the "kaiju" (giant monster) genre for a new type of screen monster. The result is a bizarre blend of film noir style gangster movie and science-fiction.

In Tokyo, a police investigation of a gang-land drug deal takes a strange turn when one of the gangsters, Misake (Hisaya Itou), apparently vanishes in the middle of a street, leaving all his clothes and posessions behind. The police, Misake's gang, who believe he has betrayed them, and a rival gang, who believe Misake's gang has betrayed them, all target his girlfriend, nightclub singer Chikako Arai (Shirakawa), who they all believe is hiding Misake or at least knows where he is. Only assistant University professor Masada (Sahara) knows the truth, radioactive fallout from hydrogen bomb tests is causing people to dissolve into living slime, anyone who the slime creatures (or "H-Men") touch similarly melt into living slime.

Mostly the film doesn't work. Neither the science-fiction or the gangster elements are really developed well, and they don't really mix well. The creature effects are mostly slow-moving slime, with the dissolving effects mainly being achieved by what appear to be deflating body-shaped balloons covered in gunk and bubbles, and the occasional appearance of blurry, green, out of focus figures who don't do anything except stand around. Also the amount of characters being covered in slime is way too reminiscent of those kid's TV shows where the losers end up being dunked in brightly coloured gunge. The film deserves some points for at least trying something new, and if you're in the right frame of mind you can have fun with it, because there is quite a lot of unintentional humour.

As with many Japanese science-fiction films of the period, this has a strong anti-nuclear bomb message, which is understandable given that it was only thirteen years since the atomic bombs were dropped on Hiroshima and Nagasaki.